On Thursday, Trump tweeted that the United States, Mexico and Canada had put together a "STRONG" pitch to host the World Cup, which is held every four years.

"It would be a shame if countries that we always support were to lobby against the U.S. bid," Trump tweeted. "Why should we be supporting these countries when they don’t support us (including at the United Nations)?"

The U.S. has put together a STRONG bid w/ Canada & Mexico for the 2026 World Cup. It would be a shame if countries that we always support were to lobby against the U.S. bid. Why should we be supporting these countries when they don’t support us (including at the United Nations)?

FIFA provided a statement to Reuters that said while soccer's governing body doesn't address specific comments made about the bidding process, it does have regulations for countries competing to host the games.

"We can only refer to the FIFA Regulations for the selection of the venue for the final competition of the 2026 FIFA World Cup, and in particular to the Bid Rules of Conduct incorporated therein," FIFA said.

As Reuters noted, those regulations warn against competing government's participating in activities "that may adversely affect the fairness of the Bidding Procedure and/or may cause any undue influence on the outcome of the Bidding Procedure."

Reuters also noted that FIFA has faced ethical questions with bidding countries in the past.

Philadelphia has been selected as one of the finalist cities for the North American bid. In a letter to Trump earlier this year, 43 U.S. senators — including Bob Casey and Pat Toomey of Pennsylvania, Cory Booker and Bob Menendez of New Jersey and Chris Coons of Delaware — endorsed the North American bid.

Ajeenah Amir, spokeswoman for Philadelphia Mayor Jim Kenney, agreed with the endorsement, telling PhillyVoice "the city would be a prime location for some of the matches."

Morocco has also placed a bid for the 2026 World Cup. France has already said it will vote for Morocco, while Russia has said it will back North America, according to Reuters. Each FIFA member country gets one vote.